Best available copy



Jan. 3, 1928.

c. PAROLINI ET AL SOUND REPRODUCING APPARATUS FOR DISK RECORD TALKING MACHINES Filed May 16. 1924 I11 z/ehto r'Sj I (Q We;

Patented Jan. 3, 1928.

UNITED STATES 1,555,1' PATENT OFFICE.

CESABE PABOLINI, OF LE VESINET-SEINE ET OISE, AND GUSTAVE PERBON, OF PARIS,

FRANCE.

SOUND-PRODUCING APPARATUS FOR DISK RECORD TALKING MACHINES.

Application filed Kay 16, 1824, Serial No. 713,677, and in France July 12, 1923.

The present invention relates to soundreproducing apparatus of the conical diaphragm ty e comprising an inverted cone open at its ase, the apex of. which carries a stylus mounted directly upon it and resting upon the record groove, or which is connected by an arrangement of levers to the said stylus, which latter may be a sapphire or a renewable needle.

The drawback of that kind of sound re producers of this diaphragm type are that such apparatus must necessarily be of large dimensions in order to be capable of compensating for the absence of the usual amplifier sound horn or trumpet, thus necessitating the. rovision of devices for tensioning the wa ls of the cone in order to mamtam it always taut in spite of the variations in temperature or the c anges in the hygrometric state of the surrounding atmos here,

and also the use of devices for regu ating the vibrations of the said walls for'the purpose of obtainin the best possible reproduction of the soun The present invention has thus for its 91)- ject to remedy the various drawbacks abovementioned, and also to rovide an improved sound reproduce! of t 's diaphragm type which shall be audible in all directions, and it consists, for this n in the combination of a conical diap ra of the same kind and of the same materials as those already known, with an amplifying sound horn. or trumpet of suitable shape, the connection between these two devices being effected at the open base of the diaphragm by means of ,a flexib e member that will stop the vibrations of the conical wall of the diaphragm, so that these vibrations shall not be transmitted to the wall of the sound horn or trumpet.

In order to enable the invention to be fully understood a constructional form thereof is hereinafter described and illustrated by way of example diagrammatically in diametral section in the accompanying drawin As s own, 1 is an inverted conical diaphragm open to the atmosphere; its base or wider edge is attached by means of an adhesive, or is fixed in an other manner, to a flexible rubber ring 2 to which there is likewise attached by means of an adhesive or fixed in any other manner the of an amplifying sound horn or trumpet (here,

inafter called the conical amplifier) made of metal, and preferably of truncated conical form with a large opening or base and small depth.

Near the small end of the conical ampli tier 3 are fixed the ends of a spider 4 of metal or other rigid material having two, three or four arms. This spider, which is arranged outside the diaphragm 1, and is situated close to the latter, comprises at its centre at the intersection of its arms a ring or orifice5 the centre of which coincides with the apex of the conical dia hragm 1, and through which passes freely tlie vertical portion of the rocking lever 6 connecting the apex of the diaphragm 1 to the stylus 7. This lever 6 is mounted so as to rock on an axle 8 carried by a bearin eye 9 that is fixed to one of the arms of t e spider 4.

The attachment of the end of the rocking lever 6 to the apex of the conical diaphragm 1 (which is composed of a light but strong material such as strong paper, moulded lastic material, &c.,) may be consolidate by means of a conical metal reinforcing washer 10 to which the vertical upper end of the said lever 6 is riveted, soldered or otherwise fixed. For the purpose of supporting the entire reproducer of the diaphragm type improved according to this invention whilst nevertheless allowing it to have free vertical and lateral play in order that it shall follow" the undulations of the spiral groove of the record on the surface of the disks, any of the usual phonograph or other supports may be employed, for instance the one shown which consists of a double ball-and-socket joint 11 fixed'at one side to one, two or more points close to the base of the conical amplier 3, and at its other side to a pillar bracket 12 mounted on the box enclosing the mechanism of the talking machine.

It isto be understood that the apparatus for attaching and holding the entire reproducer shall always be so situated as to be opposite the stylus 7 in one and the same vertical plane when it is'being used for nepro ducing phonographic recording disks. For the reproduction of gramophone records, the point of attachment of the conical amplifier 3 must be shifted into a position in which the vertical plane passing through the said point of attachment and the centre or apex of the apparatus shall enclose an angle at a out 90 with the vertical plane or the melt 310 ing movement of the lever 6, since it is not absolutely necessary that the entire apparatus shall be maintained parallel to the surface of the record disk; in fact'it may be given any desired inclination by altering the height of the joint 11. 7

As a constructional variant of the improved reproducer of the diaphragm type, and with relation to the reproduction of phonographic records, the apparatus may be simplified by fixing the stylus 7 direct-l to the apex of the conical diaphragm 1, w llCll arrangement allows of dispensing with the spider 4, the ring 5 and the rocking lever 6.

It is to be understood that modifications, alterations and improvements may be made in the practical construction of the improved reproducer of the diaphragm type without thereby departing from the nature of the invention. For instance the solid or hollow rubber ring 2 may be replaced by a circular band of caoutchouc or fabric the two edges of which are respectively fastened to the edges or ends of the diaphragml and conical amplifier 3 by means of an adhesive or in any other manner.

That what we claim is z 1. An acoustic device comprising a conical diaphragm having an open base, a frustoconical amplifier horn having its smaller base approximately equal to and adjoining the open base of the diaphragm, said amplifier and diaphragm having a connectionbetween their adjacent bases preventin the transmission of vibrations between t em, and means connected to the diaphragm for imparting vibrations thereto..

2. An acoustic device comprising a conical diaphragm having an open base, a frustoconical amplifier horn having its smaller base approximately equal to and adjoining the open base of the diaphragm, said amplifier and diaphragm having a connection between their adjacent bases preventing the transmission of vibrations between them, said connection including an interposed body of resilient rubber, and means connected to the diaphragm for imparting vibrations thereto.

3. An acoustic device comprising a conical diaphragm having an open base, a frustoconical amplifier horn having its smaller base approximately equal to and adjoining the op'en base of the diaphragm, a ring of resilient rubber interposed between and connected to the adjacent bases of said amplifier and diaphragm, and means for causing vibrations of said diaphragm.

4. An acoustic device comprising a conical diaphragm having anopen base, a, frustoconical amplifier horn having its smaller base approximately equal to and adjoining the open base of the diaphragm, said amplifier and diaphragm having a connection between their adjacent bases preventing the transmission of vibrations between them, a frame connected to the amplifier and extending into proximity to the apex of the diaphragm, and means supported by said frame and connected to the apex of the diaphragm -for imparting vibrations to said diaphragm.

In witness whereof, we hereunto subscribe our signatures.

CESARE PAROLINI. GUSTAVE PERRON. 

